A chance encounter with Andrew Lloyd Webber at a summer party sent Josceline Dimbleby on a quest to uncover a mystery in her own family's past. Her great-aunt Amy Gaskell was the subject of a beautiful dark portrait by the Pre-Raphaelite painter Edward Burne-Jones, but all that was known about Amy, according to family lore, was that she had 'died young of a broken heart'.

In her search, Josceline discovered a cache of unpublished letters from Burne-Jones to her great-grandmother May Gaskell, Amy's mother.They formed a passionate and prolific correspondence, of up to five letters a day, from the last six years of the painter's life. As she read, more and more questions were raised: why did Burne-Jones feel he had to protect May from an overwhelming sadness? What was the deep secret she had confided to him? And what was the tragic truth behind beautiful Amy's wayward, wandering life, her strange marriage and her unexplained early death?